Contractor NRG has started a series of directional drillings under the dunes at Maasvlakte this week, a key step in Dutch grid operator TenneT’s project to connect offshore wind energy from the IJmuiden Ver wind areas to the onshore electricity grid.
The work is part of preparations for the landing of high-voltage sea cables that will link future offshore transformer platforms to the national grid. Six horizontal drillings will be completed in the coming days, with three more planned after the summer, according to TenneT.
“This time it concerns drilling for the grid connections of the IJmuiden Ver Beta and Gamma wind energy areas,” said Robert Wijnholds, a project representative at TenneT. “The cables will later be installed in the seabed by the Swedish manufacturer and contractor NKT, up to the location where the transformer platform at sea will soon be built.”
The drilling, which is being conducted by a consortium of Denys, Alsema, and Van Vulpen under the name NRG, involves the use of an electric drill to bore horizontally beneath the dunes and beach for around 200 metres. An empty plastic casing is inserted into each borehole to house the electricity cables, which will be installed at a later stage.
NRG has previously carried out similar work for TenneT at Heemskerk/Wijk aan Zee and Velsen. The process is conducted in three stages: first a pilot drill is made, then the hole is widened with a reamer, and finally, a casing pipe with a diameter of nearly half a metre is pulled into place.
“They are now doing this a total of six times,” Wijnholds added.
The full cable system will operate at 525,000 volts and will include four components: two conductors, a metallic return, and a fibre optic line for remote monitoring and control.
“The metallic return ensures that the system can continue to use half of its capacity in the event of a cable failure,” said Wijnholds. “All systems at sea will soon be remotely controlled via the fibre optic cable.”
The offshore cables are scheduled for installation in 2026 and will be buried several metres deep in the seabed and beach. Onshore, they will connect to high-voltage infrastructure currently being installed behind the dunes. A live view of the drilling activities is available from the Noordzeeboulevard information point.
